Rock your world

Gardening with rocks may not sound to your friends like you’re a whiz with green things, but, in the gardening world, rocks are really hot. In fact, British customs officers have a major problem with Dutch and Belgian rock smugglers stealing them for their gardens! But Alaskans rarely have a shortage of glacial ornaments for their gardens.

While rock gardens evoke images of gravel, rocks and tiny alpine plants, I like to garden with boulders the size of grocery carts surrounded by lush greenery and a striking architectural plant. Think Japanese garden boulders with a native red currant bush all under planted with blue hostas and low-growing geraniums. The currant flowers in spring, has strings of ruby berries in summer, and orange fall color. The hostas maintain their blue foil while the geraniums flower and many varieties have lovely red fall leaf colors. The added bonus is the winter sculpture the currant bush and the boulder provide in a sea of white snow.

A simple rock garden can be designed around just one great boulder or an odd few of differing size. Surround the whole with landscape cloth, leave an area of good garden soil around the boulders, and cover the cloth with washed 1-inch gravel to a depth of at least two inches or more. Goose egg-sized rocks that you find on your hikes make a nice textural comment on the gravel bed. You might even look for a boulder that could double as a trough for plants.

Next, find your plants. You need at least one small shrub type for height. Be inventive here. Native plants such as willows can be rooted easily from cuttings. Domestic currant bushes provide beauty as well as useful berries. Those woodland terrors, the devil’s club, make wonderful stand-alone plants with ornamental berries, leaves, and alien modern art sculpture in winter. Tall herbaceous perennials that die back to the ground in winter, such as thalictrums, monk’s hood or colorful yarrows can add height in the summer.

The base of the boulders can shoulder their way out of the ground surrounded by cushiony plants like geranium Karmina, blue oat grass, sedum Red Dragon and hens and chicks Sanford Hybrid. Leave a spot open in the gravel for planting without a boulder where you can plant a mass of medium-height perennials such as columbines, with interesting variegated or bronzy foliage. Cut back after flowering, their foliage poufs up with fresh growth. Early flowering trollius reblooms if deadheaded as well.

Where you place your rock garden will determine what kind of plants you’ll need. If it’s a hot and sunny spot, you can put some semi-shade lovers behind the rock in the shade. Most succulents and silvery-leaved plants will love this sun. Experiment with a plant that has a marginal zone here, as it will be protected by the rock as the mass will retain heat and block the wind. My hostas love full sun under a rock. If you have a small yard and would rather have veggies and herbs, why not grow them in a rock garden design? Beautiful lettuces, sage, variegated lemon thyme, perennial herbs like sorrel, chives and lovage are quite ornamental and useful. Mass plant some alpine strawberries for a ground cover. Don’t forget the champagne!

Remember, artistically, less is more. Don’t overwhelm your design with too many different varieties of plants. Look for plants that have all-season interest such as foliage, flowers, seed pods, fall color and texture. And vary the foliage shapes and colors of companion plants as well.

Even though your boulders offer a sculptural statement by themselves, a special potted conservatory shrub like a bonsai choke cherry would complement your garden. That rusted chunk of interesting metal your teenager brought home from a fishing trip might do well balanced on a slab of recycled concrete. Or drive a 6-foot piece of Rebar into the ground and tie your old fishing rods to it and spray them all one color. And if you have an urge to use pink flamingos, by all means, mass them in a large cardboard box and seal it with duct tape. Then kick it into the closet.

The point is to enjoy your garden and have fun with it.

Brooke Heppinstall, artist and gardener, is the owner of Wool Wood Studio & Gardens, an art studio and nursery specializing in Alaska-grown perennials and shrubs. Visit online at Woolwood.blogspot.com.